Moonbase 3 is a lunar outpost operated as a joint European science project. Other nations also have moon bases, including the United States and Russia. After Moonbase 3’s director is killed in a shuttle accident in route to Earth, a new director is assigned to the base. The new director, David Caulder, must investigate the accident which killed his predecessor and a shuttle pilot of questionable mental health. His job is complicated by a series of accidents and deaths on the station. Caulder must also deal with the psychological effects the crew is suffering while working under the added pressure of convincing headquarters in Brussels that the moon base is a worthwhile scientific project and an economically sound investment.